


Not All Spirits Are Demons

by TwilaFrost



Series: Sakusa Week 2020 [3]
Category: Haikyuu!!
Genre: Alternate Universe - Demons, Demon Slayer Sakusa, Kitsune, M/M, Mild Language, Non-Graphic Violence
Language: English
Status: Completed
Published: 2020-09-21
Updated: 2020-09-21
Packaged: 2021-03-07 22:41:46
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,135
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26585308
Author URL: https://archiveofourown.org/users/TwilaFrost/pseuds/TwilaFrost
Summary: Sakusa is a demon slayer heading to a small town for his next mission. He feels a strange aura from two of the town's residents. They aren't the demons he's after, right?
Relationships: Miya Atsumu/Sakusa Kiyoomi
Series: Sakusa Week 2020 [3]
Series URL: https://archiveofourown.org/series/1931530
Comments: 18
Kudos: 187





	Not All Spirits Are Demons

**Author's Note:**

> Did I just essentially make this a Demon Slayer AU? Yes. Do I regret it? No.
> 
> Sakusa Week 2020 Day 3: Demon/God

Even though he has barely put away his sword, a new mission is already waiting for Kiyoomi. There have been reports of young girls going missing in a town not too far from where he is now. There’s no doubt that it’s the work of a demon. Only a demon is capable of something so grotesque as eating a human being. If they are sending him, it must be strong, he’s one of the top slayers in Japan after all. The creature he just dealt with wasn’t necessarily powerful, it was just crafty. He hopes this one is all brute strength and no brain. The intelligent ones are annoying. Needing to get a move on, he begins his next journey, yellow and green haori fluttering in the wind. 

As soon as Kiyoomi sets foot in the town, he can feel the demonic presence. There’s more than one. It’s not exactly a problem, he’s dealt with multiple demons at once before plenty of times. The issue here is that they don’t feel like your average demon. Something in his gut tells him that this mission is not going to turn out as planned. 

Since it’s daylight, he won’t be able to track the demon properly. That’s why it’s heavy presence is so unsettling. It shouldn’t be strong like this when the sun is out. Night is the demons’ domain. Another strange thing Kiyoomi notices walking through the town is that it’s based around an Inari shrine. That alone should ward off demons. What kind of demon is he dealing with exactly? 

He’s jolted from his musings by a loud crash behind him. There’s a man about his age with black hair in a blue and white half circle patterned haori over a dark blue yukata running away. Another boy, nearly identical, is laying on the ground. He has blonde hair and a gold and black hanafuda haori over a black yukata. The crash must have been the wooden crate now on the ground with an assortment of items scattered around it. 

“‘Samu, get back here ya fiend!” The one on the ground yells at the retreating figure.

The owner of the stall he’s standing by chuckles at the scene. “Ah, the twins are at it already today.” Kiyoomi turns slightly to her as if he’s listening. He needs to gather some sort of information. When she sees his interest, she elaborates. “They’re the Miya twins, and they always manage to liven up the place. They take care of the shrine.” He nods his thanks.

Perfect. Shrine keepers are more in tune with the otherworldly and may have noticed something. He approaches the blonde Miya and helps place some stray items back in his crate. This close, Kiyoomi feels a strange energy radiating from him. He can’t place it, and he doesn’t like that. It’s not quite like the aura he gets from the demons he slays, but it’s similar. But it’s day time. This man can’t be a demon, right? 

“Thanks,” Miya says then looks up with raised eyebrows. “I don’t recognize ya. Ya new ta town?”

“I just arrived today, and I’m rather interested in the shrine here.”

“Well, ya found the right person! I’m Miya Atsumu,” he bows in greeting. “My no good brother, Osamu, ran off.” 

“Sakusa Kiyoomi,” he returns the gesture. He also doesn’t miss how Miya’s eyes linger on his Nichirin blade. 

On the way up to the shrine, Miya doesn’t stop talking. Kiyoomi regrets not just coming up here on his own. He’s going on about fox spirits and such. They’re all demons in Kiyoomi’s book. Any strange apparition on the material plain will meet the sharp end of his blade. He looks to the blonde man by his side. As they get closer to the shrine, the energy seems to increase. What is he? 

“Alright, Omi-kun! C’mon inside and I’ll make some tea.” 

“It’s Sakusa.” He grumbles, following Miya inside the small home settled near the shrine.

The man ignores him and walks to his brother, who has wandered into the room. He leans in and whispers something in his ear. The bored looking twin’s only outward reaction is a slight twitch of his eyebrow. He then seems to size Kiyoomi up before leaving the room once again. 

“Ah, don’t worry ‘bout him. He’s not a big people person.” Well, Kiyoomi isn’t a big people person either, so he can relate. He begins boiling a kettle over the fire as he talks. “So what’re ya interested in ‘bout the shrine?”

“Actually, I want to know if you’ve felt anything off with the shrine recently.” 

It’s not like he can right out say anything about demons, as most people would write him off as crazy. However, he might be able to get something more out of Miya since he was talking about fox spirits earlier. 

“What’d ya mean by off?” He tilts his head in a very canine way. 

“Have you felt a foreign or ominous presence around?” 

Miya sets two tea cups on the table and motions for Kiyoomi to sit. He takes his own place across from him. “Can’t say I have. Why’re ya askin’ strange questions like that?”

“There have been reports of young women going missing around here. I’m looking into it.” 

Miya’s face falls at the mention of the disappearances. “Ah. The culprit’s quite elusive. One moment the girls are there, the next they’re gone.”

“So you really haven’t seen or felt anything?” 

“Nope,” he pops the p and leans back in his chair, appraising Kiyoomi. “I assume you’re gonna look for this guy?” 

“Yes, it’s my job.”

“When you’re out there, jus’ remember who the real enemies are.” Miya has a serious look on his face for the first time since Kiyoomi met him. His words are full of hidden meaning. Miya is definitely hiding something, he just has to figure out where it fits in the puzzle. 

As night falls, Kiyoomi is already patrolling the streets. Miya’s words from earlier ring in his ears. The real enemy? The enemies are demons. Whatever Miya is, Kiyoomi isn’t entirely sure it’s human. If he’s a demon, then he’ll have to die. That’s just how it is. 

The demonic presence is shifting. It’s on the hunt. Kiyoomi runs toward the source of the energy. He’ll take care of this in no time. The scene he runs in on, though, is not what he anticipated. 

Both Miyas stand protectively in front of a young woman while a hideous, ashen grey horned creature bares its jagged teeth at them. Are they stupid? This thing will rip them in half!

“‘Bout time ya showed up,” Miya says upon Kiyoomi’s arrival. “‘Samu, take Mai ta safety. Omi-kun and I will handle this scrub.”

His brother nods, picking up the girl with minimal effort and taking her away. What the fuck is Miya going to do exactly? It’s not like he has a blade. 

“Get out of the way, Miya. You’ll only hinder me.”

Kiyoomi dashes toward the demon, wielding his blade for a precise and lethal strike. However, the demon disappears right before he makes contact. The hell? The demon, now on a roof, cackles down at him. 

“So they’ve finally sent a slayer, have they? Too bad for you fox boy,” he sneers at Miya who only has a determined glint in his eyes. 

Great, so this one’s a talker. How annoying. He glances towards Miya. Fox boy?

“What, you aren’t going to give him a show?” The demon taunts. Kiyoomi isn’t sure which of them it’s talking to. 

Miya wearily looks over at him, “Remember what I told ya.” Then he sprouts five fluffy black tails with blonde tips and ears of the same color, before jumping onto the roof with remarkable athletics.

Fuck. He is a demon. The strange energy Kiyoomi felt from him has multiplied, causing him to stumble slightly in surprise. If these demons are going to fight each other, then Kiyoomi has to take advantage of it. He’ll have to deal with Miya after this other one is dead. 

Kiyoomi follows the demons onto the roof where they are already engaging each other. Miya has summoned some sort of demon fire magic that he’s throwing towards the other. Kiyoomi takes his chance to slice the demon from behind but is blocked by its long claws. Its other hand swipes at him as he ducks away. 

“You foxlings may have fought off my brethren, but I am by far the strongest.” This demon really is a moron if he thinks that’s intimidating. 

Faster than the eye can see, the demon spins around and crashes into Kiyoomi. He kicks the demon away and prepares for another attack. Miya pounces on the demon as it tries to regain its balance. His hands alight with fire, burning the demon. It cries out in pain and anger. 

With the demon essentially pinned, Kiyoomi easily cuts through its neck. It slowly disintegrates into black dust, blowing away in the wind.

“Tch. So much for bein’ the strongest. What a scrub.” Miya is looking down at the remains with a hardened scowl. 

Right, he has to take care of this one now. Raising his blade again, Kiyoomi makes a move to decapitate the fox demon. Miya must sense him, for he easily sidesteps.

“Whoa, whoa! I thought we were cool, Omi-kun!” 

Kiyoomi looks at him with a blank expression. “You’re a demon. I have to kill you.”

Miya looks at him like he’s stupid. “I’m not a demon ya moron! See, I knew ya were the type ta think anythin’ unnatural must be evil. Do ya know nothin’ of myth and legend?”

The slayer stares at him. This demon is trying to trick him. There’s no other explanation. He’s never encountered anything like this that’s _not_ evil. Most spirits are malevolent, and therefore fall under the class of demon. To Kiyoomi at least.

The fox demon throws his hands up in exasperation. “Are ya serious?! I’m a fuckin’ kitsune! Ya know, messengers of Inari? The one’s ya gotta watch are nogitsune. Those guys are lil’ bastards.” 

There are different kinds? “How do I know you aren’t trying to trick me.”

Miya looks entirely unamused, “Please tell me ya ain’t this dense.” When Kiyoomi says nothing, he throws his head back and groans. “I live in a fuckin’ shrine, ya absolute cretin!”

Well, he supposes that makes sense. No demon would be able to live around a shrine like that for an extended period of time. Kiyoomi assesses Miya, who is tapping his foot impatiently. The demonic energy he felt is gone now. All that remains is the strange aura Miya is emitting. His instincts tell him this is not bad energy. Now he’s rather interested in this type of spirit. Maybe it’ll be useful information in the future.

“So you’re a benevolent fox spirit?”

“Oh thank Kami ya finally get it! Ya don’t have many friends do ya? It’s too bad, ‘cuz ya have an awfully pretty face.” 

Kiyoomi frowns but decides to let it slide. He did just try to kill him after all. 

“I want to learn about the other spirits that visit the material plane.”

Miya raises an eyebrow, a smug smirk displayed on his face “Oh? Well, let’s make a deal. Ya teach me how to use one of those,” he points to Kiyoomi’s blade, “and I’ll answer all yer questions.”

It’s then that his crow informs him of a new mission. Dammit, he doesn’t have time to indulge Miya in this bullshit. He just wants the information. 

“I have to leave now since my job is complete.”

The fox man tilts his head, “Well, looks like ya got yerself a travellin’ partner.”

“No. Absolutely not.”

“I think ya owe me for tryin’ ta slice me in half. Besides, you’re really gettin’ the better end of the deal here. Ya get a powerful fightin’ companion, useful information, and my spectacular company!”

The only thing Kiyoomi needs out of that is the information. He’d leave the rest if he could. Is this even allowed? Travelling with a spirit? 

“I can hear ya thinkin’ Omi-Omi. Don’t ya wanna wake up to my handsome face every day?” 

Kiyoomi will never admit that he’s nice to look at. It will follow him to his grave. Dammit all to hell, he’s actually going to agree to this. 

“Fine.”

“Yes!” Miya whoops in excitement, actually jumping in the air like an overexcited child. “Well, then c’mon! Let’s go back so I can get my stuff and tell ‘Samu.”

Miya starts off in the direction of his home, leaving Kiyoomi there, still on the rooftops in the dead of night, to contemplate his life decisions. 

He’s going to regret this, he’s sure of it.


End file.
